


The Littlest Life Changer

by delicatehedgehog



Category: Hunter X Hunter
Genre: Age Regression/De-Aging, Alluka comes in clutch, Canary/Amane Mentioned, Drugged Drink, Established Relationship, Family Bonding, Happy Ending, Hisoka isn't a creep i promise, Illu loves naptime, Illumi turns into a toddler, Implied/Referenced Child Abuse, M/M, Minor Character Death, Nen (Hunter X Hunter), No Smut, Silva sucks, Tiny Illumi Supremacy
Language: English
Status: In-Progress
Published: 2021-02-07
Updated: 2021-02-15
Packaged: 2021-03-12 05:55:52
Rating: Mature
Warnings: Graphic Depictions Of Violence, No Archive Warnings Apply
Chapters: 2
Words: 3,167
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29255577
Author URL: https://archiveofourown.org/users/delicatehedgehog/pseuds/delicatehedgehog
Summary: Illumi switches his and Hisoka's drinks when he notices a mysterious new bartender slips something into Hisoka's drink, thinking it's a simple drug. After consuming the drink, both of them realize that this was nothing of the sort, now what will Hisoka do with Illumi now that he's become a toddler? Somehow, this interesting development seems to cut through the ever-present tension that's overtaken the Zoldyck household as of late. Nen exorcists are unable to reverse the effects of the nen infused drug, so will Illumi be returned to his original state, or will he be permanently stuck in his toddler form? That all depends on whether or not they can track down and communicate with Killua and Alluka, and whether they're willing to help.
Relationships: Hisoka/Illumi Zoldyck
Comments: 6
Kudos: 67





	1. That Night

The bar was buzzing with its usual level of customers, light music that could barely be heard over the sound of drunken voices chatting amongst each other. The smell of booze filled the place, though, it was a smell that felt refreshing, calm, and overall pleasant. Hisoka and Illumi reserved their usual table and ordered two lemon-drop martinis. There was a new bartender this time; a young, tall, blonde woman with dull green eyes, though those dull green eyes hardened greatly at the sight of Illumi’s beloved magician. As the drinks were bestowed upon them, a small, quickly dissolving pill was dropped into Hisoka’s drink with such a skill that it could only be picked up by Illumi himself. 

As Illumi picked up the drinks to bring to their designated table, he gave Hisoka the drink meant for him, while he took the one the mysterious bartender tampered with. He’s immune to poison, surely this is nothing more than the simple; slip in the drink and your victim’s out cold in minutes kind of drug, nothing special. Though it was tasteless, scentless, if Illumi hadn’t seen the tampering, there wouldn’t have been any signs of it whatsoever. This is suspicious. 

Her name tag says Ena, so at least I have that information. It would be too risky to confront and kill her here. Maybe I can get Milluki to find some information on her when we-

“Illu, darling~ Is everything alright?” Hisoka cocked his head in concern, “You’re really pale.”

“I should be fine, ‘Soka, maybe it’s the weather?” Illumi was dumbfounded, drugs, even ones that would make an elephant drop dead in minutes, hadn’t affected him since he was a child, surely it was the weather. Right?

“Maybe, we should leave early tonight. There’s always next weekend, darling,” he ran a finger through Illumi’s silky, long hair. Illumi nodded and left the bill at the table, along with a hefty tip just for the sake of tipping; his mother raised an assassin, not an asshole. 

~~

The air of the parking lot was chilly and crisp, the crescent moon shining above them. Illumi walked in front, though he was beginning to shake. Hisoka’s eyes widened as he sped up his pace.

“Illu, maybe I should drive, you don’t look so-” he was cut off by a puff of smoke surrounding Illumi. Then, Illumi was gone, or so he thought. Eyes wide, looking down at a tiny, slightly moving lump covered by his fallen clothing. Hisoka crouched down, still in disbelief at the sight before him, “Illu?”

A little head poked out of the bundle of clothes. Short, shaggy black hair, black eyes far too big for that little face, and a curious expression that quickly molded into one filled with tears and quiet whimpers. Tiny hands raised up with the intent to be picked up, Hisoka felt a slight relief, the tiny Illumi recognized him. He quickly picked up the tiny child and bundled his close around him, making his way to the car as quickly. Little arms clinging to his shoulders as silent tears rolled down his face. There obviously wasn’t a car seat in the car, so Hisoka simply held onto Illumi tightly as he sped back to Kukuroo Mountain. He didn’t bother calling anyone, he didn’t know how to explain it anyways. What took minutes felt like hours, but they finally reached the testing gate. Holding a now sleeping Illumi snugly with both arms, one arm supporting him, one arm stroking his little head, he kicked the testing gate open with ease, opening up three doors in the process.

It wasn’t long before they reached Canary’s post, she was talking casually with Amane before an abrupt silence overcame the two as they saw Hisoka carrying the little boy bundled in Illumi’s clothes. 

“Good evening, Master Hisoka,” they greeted, almost in unison, but not quite. 

“Where is Master Illumi?” Amane asked softly but firmly. Amane was one of Illumi’s favorite butlers, they had known each other since they were small children, she always seemed to know when something was off.

“It’s a long story,” Hisoka sighed with a frustrated look on his face. Illumi began to stir in his sleep and eventually woke up, looking up at Hisoka with sleepy eyes and raising a single tiny hand to Hisoka’s cheek. Hisoka grabbed his hand and gave it a little kiss, earning a small smile from the child. Amane’s eyes widened in realization, Canary hadn’t quite caught on yet. 

“I-is that- Master Illumi?” Amane stuttered out. Hisoka nodded and began walking forward. 

“There was a strange bartender that slipped something in my drink, but Lumi switched our drinks thinking it was just a regular poison, and this happened. I don’t know anything else, honestly,” he replied before walking away entirely, after getting a confused nod from the two butlers. After a while, Illumi had fully woken up and was giggling and playing with Hisoka’s earlobe.

“Hiso, Hiso,” he said eagerly, looking up at the magician who smiled down at him. Giant black eyes met narrow golden ones.

“Yes, doll?” Hisoka replied. A little finger reached up to his nose, giving him a poke.

“Boop!” Illumi grinned at him before quickly resting his head back on Hisoka’s surprisingly comfortable shoulder, his little mop of black hair falling in his face as he fell back asleep.

How the hell am I going to explain this to Kikyo?


	2. Mother's Love

It wasn’t long before they reached the main estate, and Hisoka raced inside. Though he wasn’t quite running, that would probably wake Illumi up. He hoped and wished for Kikyo to still be awake, she’s always been a night owl, so this better not be the one night she decides to sleep early. And like that, his internal wish was granted, and he was met with Kikyo reading a book on the couch. Legs crossed, and her usual bustle gown replaced with a toned-down, yet still extravagant long black nightgown accompanied by a purple mesh robe with fur lining the hemming, the kind a woman would wear to be confronted by the police about her husband dying under mysterious circumstances. She was still wearing her visor, but her hair was down and her bandages were nowhere to be seen. She looked up from her book, only seeing Hisoka at first.

“Oh, hello Hisoka. Where’s-” Kikyo’s face distorted in shock at the sight of the bundle in his arms, recognizing her darling little Illumi immediately, “WHAT DID YOU DO TO MY BABY YOU CLOWN?!”

Before Hisoka could respond, Illumi stirred in his arms and his head bolted in the direction of his mother. Eyes wide with a short, open smile plastered on his little face. He reached out to Kikyo with both arms, making little grabby motions with his hands. Her face softened at the sight of the child.

“Mama!” Kikyo took her baby from Hisoka’s arms, taking the bundle of clothing along with him, stroking the back of his head and hair gently. Immediately, he rested his head on her chest and began to play with the “earrings” dangling from her visor. 

“Well, we were at the bar like we usually are on Friday, and there was a new bartender, a blond chick named Ena~, Illu must have switched our drinks thinking it was a standard poison. He started feeling sick so we went out to the car, but when we were in the parking lot, there was a puff of smoke, and that brought us to where we are now,” Hisoka rested his chin onto his palm as he sat on the living chair.

“How am I supposed to believe that  _ my son _ took some sort of mystery drug, went ‘poof,’ and turned into a toddler? That makes absolutely zero sense,” if Kikyo’s eyes were visible, they would appear narrowed in annoyance. How  _ was _ she supposed to believe that? 

“Well, we could have Milluki check the security cameras~” he suggested, “On another note, are there any clothes around here that would fit the little darling? I highly doubt that he would enjoy being stuck in a bundle of adult clothing all the time.”

“That does sound like the best option, and yes, we do,” Kikyo replied, “I keep all of my children’s childhood clothing in the room in between Milluki and Kalluto’s rooms.”

“Got it~” he stood up to retrieve them but was abruptly stopped by Illumi grabbing him by his wristbands.

“Don’t go Hiso,” he pleaded with his trademark big puppy eyes that Hisoka could  _ never _ say no to, even in his adult form. He waited for Kikyo’s gesture of approval before scooping Illumi into his arms and giving him a soft peck on his hair-covered forehead, receiving a giggle, scrunched up a smile, and a hug around his neck.

“I would never leave my little Illu alone,” he smiled before turning around and making his way to that room, Kikyo following close behind the pair. Illumi was preoccupied with being mesmerized and playing with Hisoka’s dangle heart earrings, they were just so shiny. 

Kikyo then unlocked the door to the abnormally large, two-story bedroom-made-closet for all the no longer used items her children have once had, mostly clothing and toys. It wasn’t like a hoarder’s room; it was elegant, organized by age, style, and color. The first decision was the easiest, getting an outfit for Illumi to wear right now, Hisoka quickly settled on a medium brown onesie which had ears on the hood and paws on the feet, it was unrealistically soft and Illumi took an instant liking to it, snuggling into it the moment it was on his body. Kikyo seemed to be having the time of her life picking the next who-knows-how-long’s clothing options. An array of tiny pajamas and daytime outfits, some of those being cozy, but others being little formal outfits, she sure does love to dress up her children, damn. In the meantime, Hisoka kept Illumi busy by following his every little command; right now Illumi was pretending to be an airplane, and Hisoka was gently whooshing him around in his hands.

Milluki quickly noticed the commotion in the room, entering only to be met by Hisoka and this mysterious child that looked oddly like a teeny tiny Illumi. Before he could question Hisoka as to who and why this little kid was here, he began lightly slapping Hisoka’s hand with his hands so the latter would set him down. Once he got that wish he bolted towards Milluki, arms out in front of him before he hugged his legs tightly.

“Millu! Millu, up please!!” Illumi cheered with his arms up, releasing himself from the hug. Milluki was understandably shocked at the sight of his big, no, little brother’s shrunken form. He could definitely recognize him, there was no doubt it was him; those eyes almost too big for his face, little ears sticking out of his head, glossy black hair, and permanently airheady expression on his face. He could vaguely remember Illumi when he really was around that size; that being said, Illumi was five when Milluki was born, but that didn’t mean Illumi wasn’t an especially tiny child, a late bloomer if you’d want to save words. He was tiny up until his drastic growth spurt when he was 14, leaving him tall with long, thin limbs.

“What the hell is going on, mama?” Milluki asked as he lifted a giggling Illumi before cradling him in his arms as he did with Kalluto when he was little, the only other member of the family who inherited Illumi’s tininess. 

“We don’t entirely know yet, Mil. Do you think you could get anything from the security cameras at the bar Illumi usually goes to on the weekends? An employee there, a woman named Ena, is responsible for this; I’d like to get as much information on her as possible,” Kikyo said holding up a little tee-shirt with a frog printed in the center chest, “Would Illu look cute in this?!”

“Sure thing mama,” replied Milluki with a thumbs-up. Illumi let out a quiet, high-pitched yawn that could easily melt the heart of all three of the cold-blooded killers in the room, eyes droopy, his teeny fist rubbing one of them. Kikyo tossed the shirt into the box and sped over to her children. 

“Oh Illu is it bedtime?” Kikyo asked with her hands clasped together, wooing over the utterly adorable sight. Illumi gave a delayed nod with half-lidded eyes before reaching out to Kikyo. Just like when he was a baby, just the mention of a nap or bedtime would make him tired if he wasn’t already, the boy was always ready to sleep, he loved it. Something Silva always took advantage of, punishing him with a lack of sleep whenever he saw fit. Not much has changed about Illumi’s love for sleep, during the span of their relationship, Hisoka noticed that asking Illumi if he was tired would make him even more tired, and Illumi could always fall asleep on command no matter how long he was out, and he always dreaded waking up and getting out of bed even when he was fully rested.

Kikyo and Hisoka made their way to Illumi’s room with Milluki following close behind, not sure what to make of the situation, but concerned for his brother nonetheless. He had never heard of a drug that Illumi could be vulnerable to, let alone one that could turn him, let alone anyone, into a toddler. He had so many questions, questions that he didn’t know how to ask, but had a feeling he’d get the answer to soon enough. 

There was no point in setting up a whole nursery for Illumi when he had a room with a perfectly good bed that he was quite fond of. Not to mention, Hisoka would be able to keep an eye on him at all times, not that he wouldn’t be willing to lose sleep tending for this tiny Illumi. 

Hisoka’s entire demeanor was shattered. What once was almost unbearably self-righteous and careless, was timidly thinking about what would happen next, a thought that rarely crossed Hisoka’s mind, not in the way it was coursing through his mind right now. He worried about Illumi all the time, sure, but that was always a matter of his mental wellbeing, the occasional episode where his mind would go dark and he would destroy anything in the room he was in with tears running down his face uncontrollably before putting everything back into its place perfectly, then going back to normal, stoic Illumi. Now, he worried for his wellbeing as a whole, would he ever revert to normal, or was this a permanent change. 

The thought of contacting Killua and Alluka to ask for help kept crossing his mind, but this idea was unrealistic. Killua and Illumi were not on good terms, and regardless of that, Illumi would refuse to take Alluka’s help after he was forced by Silva to try and kill her, to treat her like a subhuman even if Alluka knew that Illumi would never really harm his darling little sister, at least not to a severe degree. Killua was unaware of that, and Alluka and Nanika really had no intention to tell him that, it would only make him angrier than his elder brother allowed himself to tell such outlandish lies when he was normally an honest man. Regardless, Illumi couldn’t forgive himself, not that he tried to anyways. Illumi wouldn’t accept help on a normal occasion, let alone something he would consider so embarrassing if the “real” Illumi was aware of the situation. Hisoka knew that all too well, he used to consider it an act of pride, but came to find out it was really a lack thereof. 

They reached Illumi’s bedroom quickly, a bedroom that looked more like a small apartment than a regular bedroom. With a giant bed that was sure to make him look tinier than he already was. Kikyo walked to the bed and gently set him down, covering him with the fluffy blankets. Illumi was nearly asleep, the only indication of his consciousness being his periodic, slow, droopy-looking blinks, and occasional shift of his hands. She planted a kiss on his temple and bid her son-in-law a good night. Something she never even considered doing until after the wedding. As the protective mother she was, she was wary of Hisoka for a good few years, as soon as they had met, she did not like Hisoka. She thought he was a weirdo for lack of a better word, and thought her son deserved a better man, someone who wasn’t Hisoka. She didn’t like his attitude, his lack of a filter even in formal situations. That all changed at their wedding, seeing their matching tuxedos, the look in their eyes. He had gotten Illumi to show the most emotion he’d shown in years that day, the glimmer in Illumi’s eyes and the small smile plastered on his face the entire event that only grew during the telling of their vows, it gave her a change of heart.

That day her eyes opened to Hisoka’s true nature, he wasn’t just a weird, perverted clown-looking man, he was someone who valued Illumi above everything else. Someone who could look at Illumi and see all of his flaws and completely embrace them, almost loving them, he was someone who truly loved Illumi just as much, if not more than she did. If she were to really look into it, she could say Hisoka worshipped Illumi and vice versa. They were truly made for her. Hisoka laid next to Illumi, gazing down at him with a look of concern and overall fondness for the little man. After she turned around to join Milluki, she let a tear trickle down her face. Milluki kept quiet, there was no point in embarrassing her while she was already emotional, he knew her better than that, and he knew this wasn’t a tear of sadness, but a tear of joy, a tear of comfort. Milluki put a single, large hand on his mother’s shoulder after they had both exited and shut the door, just in case. 

Kikyo, above all, was a mother. She was one of those women born to be a mother. Even when she was a small child living in the slums of Meteor City, even after she had been sold as a bride to Silva as a teenager, even when she was forced to allow her children,  _ especially little Illumi _ , to be tortured relentlessly under the impression that retaliation would cause certain death for the lot of them, that’s just who she was. It had been the first and only thing she’d ever truly wanted, everything, and everyone else was disposable. If someone were to describe her in one word, it would be a mother. And she shed another shockingly pleasant tear.

_ Her baby, he’s in good hands. _

**Notes for the Chapter:**

> I just wanted to explain this in a note rather than trying to squeeze this somewhere in the middle of a chapter, but here's how Illumi's situation is working. He has the mind and body of a toddler (until he gets turned back of course) due to the "drug" that Ena put in his drink. He still kind of has all his memories in the sense that he knows who everyone is and associates them with different things and relationships and shit like that. However, since he is a toddler he treats everything like a normal toddler would, like good vs bad, safe vs scary, things like that! Regular Illumi, as I'd like to put it, isn't aware of the situation he's in if that makes sense, it's like regular Illumi is sleeping, but he's also awake in the form of baby Illumi. He doesn't think "oh crap why am I a toddler," he simply just is one, I hope I've explained that alright! Anyways, I hope you're enjoying this story so far! Happy reading! :)


End file.
